Nature`s uncommon elements: Plutonium and technetium

The authors have taken advantage of the extremely sensitive method of thermal ionization mass spectrometry to measure technetium and plutonium concentrations in sample masses that are smaller by as much as three orders of magnitude than those used in the early research efforts. The work reported in this paper extends the understanding of the geochemistry of plutonium and technetium by developing detailed descriptions of their associations in well characterized geologic samples, and by using modern neutron-transport modeling tools to better interpret the meaning of the results. Analyses were conducted on samples from three uranium ore deposits selected for their contrasting geochemical environments. The Cigar Lake deposit is an unweathered, unaltered primary ore in a reducing environment which is expected to closely approximate a system that is closed with respect to uranium and its products. The Koongarra deposit is a shallow system, both altered and weathered, subject to active ground water flow. Finally, a sample from the Beaverlodge deposit is included because it is a commercially-available uranium ore standard that allows demonstration of the precision of the analytical results